The energetic characteristics of milling with changing cross-section in the definition of specific cutting force by FEM method

2021 ◽  
Vol 32 ◽  
pp. 61-69
Author(s):  
János Kundrák ◽  
Bernhard Karpuschewski ◽  
Zoltán Pálmai ◽  
Csaba Felhő ◽  
Tamás Makkai ◽  
...  
Keyword(s):  
Cutting Force ◽  
Cross Section ◽  
Specific Cutting Force ◽  
Fem Method ◽  
Definition Of

scholarly journals Structure of the Balmer jump

2018 ◽  
Vol 613 ◽  
pp. A55
Author(s):  
F. Calvo ◽  
L. Belluzzi ◽  
O. Steiner
Keyword(s):  
Hydrogen Atom ◽  
Absorption Coefficient ◽  
Total Cross Section ◽  
Analytical Model ◽  
Cross Section ◽  
Quantum Structure ◽  
Balmer Series ◽  
Polarization Phenomena ◽  
Definition Of ◽  
Rapid Drop

Context.The spectrum of the hydrogen atom was explained by Bohr more than one century ago. We revisit here some of the aspects of the underlying quantum structure, with a modern formalism, focusing on the limit of the Balmer series.Aims.We investigate the behaviour of the absorption coefficient of the isolated hydrogen atom in the neighbourhood of the Balmer limit.Methods.We analytically computed the total cross-section arising from bound-bound and bound-free transitions in the isolated hydrogen atom at the Balmer limit, and established a simplified semi-analytical model for the surroundings of that limit. We worked within the framework of the formalism of Landi Degl’Innocenti & Landolfi (2004, Astrophys. Space Sci. Lib., 307), which permits an almost straight-forward generalization of our results to other atoms and molecules, and which is perfectly suitable for including polarization phenomena in the problem.Results.We analytically show that there is no discontinuity at the Balmer limit, even though the concept of a “Balmer jump” is still meaningful. Furthermore, we give a possible definition of the location of the Balmer jump, and we check that this location is dependent on the broadening mechanisms. At the Balmer limit, we compute the cross-section in a fully analytical way.Conclusions.The Balmer jump is produced by a rapid drop of the total Balmer cross-section, yet this variation is smooth and continuous when both bound-bound and bound-free processes are taken into account, and its shape and location is dependent on the broadening mechanisms.

scholarly journals Recommendations for Reporting Ion Mobility Mass Spectrometry Measurements

2018 ◽  
Author(s):  
Valerie Gabelica ◽  
Alexandre A. Shvartsburg ◽  
Carlos Afonso ◽  
Perdita E. Barran ◽  
Justin L. P. Benesch ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Cross Section ◽  
Ion Mobility ◽  
Collision Cross Section ◽  
Ion Mobility Mass Spectrometry ◽  
Gas Temperature ◽  
Mobility Data ◽  
Community Effort ◽  
Primary Standards ◽  
Definition Of

Here we present a guide on ion mobility mass spectrometry experiments, which covers both linear and nonlinear methods: what is measured, how the measurements are done, and how to report the results, including the uncertainties on mobility and collision cross section values. The guide aims to clarify some possibly confusing concepts, and the reporting recommendations should help researchers, authors and reviewers to contribute comprehensive reports, so that the ion mobility data can be reused more confidently. Starting from the concept of the definition of the measurand, we emphasize that (i) mobility values (K0) depend intrinsically on ion structure, the nature of the bath gas, temperature, and E/N, (ii) ion mobility does not measure surfaces directly, but collision cross section (CCS) values are derived from mobility values using a physical model, (iii) methods relying on calibration are empirical (and thus may provide method-dependent results) only if the gas nature, temperature or E/N cannot match those of the primary method. Our analysis highlights the urgency of a community effort towards establishing primary standards and reference materials for ion mobility, and provides recommendations to do so. <br><br><br>

scholarly journals Specific Cutting Force Analysis of Young Coconut Husk (Cocos nucifera)

2014 ◽  
Vol 02 (2) ◽  
pp. 89-95
Author(s):  
Tika Hafzara S ◽  
◽  
Desrial Desrial ◽  
Dyah Wulandani ◽  
◽  
...  
Keyword(s):  
Cutting Force ◽  
Cocos Nucifera ◽  
Force Analysis ◽  
Specific Cutting Force ◽  
Coconut Husk

Geometric Indicators of Flexible Slice Lip

2015 ◽  
Vol 816 ◽  
pp. 188-194
Author(s):  
Krzysztof Talaśka ◽  
Ireneusz Malujda ◽  
Dominik Wilczyński ◽  
Jan Górecki ◽  
Paweł Tarkowski ◽  
...  
Keyword(s):  
Stress State ◽  
Cross Section ◽  
External Factors ◽  
Geometric Parameters ◽  
Geometric Features ◽  
Maximum Deflection ◽  
Paper Making ◽  
Definition Of ◽  
High Flexibility

The paper is thematically connected with paper making machines. This type of the machine is equipped with a head which has a flexible slice lip for skimming the pulp applied to produce the paper. The definition of geometric features of the slice lip is a key issue. The slice lip should be made of material which is resistant to external factors, and designers want to obtain a high flexibility of this element. It is possible to get a high flexibility by forming a proper shape of the slice lip. The paper presents the proposal of dimensionless geometric indicators which combine basic geometric parameters of the slice lip. These indicators are the following: indicator of the cross-section, indicator of the length and indicator of the length of the transverse notch. FEM strength analyses were done – the aim of these analyses was the determination of the stress state and maximum deflection of the slice lip. The authors have analysed the slice lip with holes for mounting the actuators and the slice lip and with transverse notches for increasing its flexibility. The results were presented in the form of graphs.

Influence of non-ideal storage conditions on carrot moisture content loss

2008 ◽  
Vol 4 (1) ◽  
pp. 61-75 ◽  
Author(s):  
Tímea Kaszab ◽  
Ferenc Firtha ◽  
András Fekete
Keyword(s):  
Moisture Content ◽  
Cutting Force ◽  
Storage Conditions ◽  
Stiffness Coefficient ◽  
Mass Reduction ◽  
Good Characteristic ◽  
Specific Cutting Force ◽  
Color Characteristics ◽  
The Impact

The objective of the work reported here was to determine changes in the moisture content, firmness characteristics, color attributes and NIR absorbance of two carrot cultivars during storage. There was a definite loss in the moisture content that caused changes in the firmness. This result shows that carrot firmness is very sensitive to the moisture content. The firmness — especially the cutting force — is a good characteristic for predicting changes in carrot moisture content during storage. The color characteristics — a* and b* — showed a slight change in the function of the moisture content. However, these color characteristics are suitable for distinguishing the phloem and xylem parts of carrot cultivars. There were not found definite changes in the NIR absorbance as the function of the moisture content. Consequently, the specific cutting force and the impact stiffness coefficient are good characteristics of the carrot moisture content and the mass reduction during storage under non-ideal conditions.

Secondary Stresses in Airship Hull Structures

1927 ◽  
Vol 31 (204) ◽  
pp. 1073-1109
Author(s):  
J. F. Baker
Keyword(s):  
Cross Section ◽  
External Load ◽  
Structural Engineering ◽  
Secondary Stress ◽  
Rigorous Definition ◽  
The Cross ◽  
Definition Of ◽  
Redundant Structure ◽  
Ball Joints ◽  
External Loads

In no branch of structural engineering is there a rigorous definition of the term “secondary stress.”If the primary stresses in a structure are determined, that is, the stresses in the members due to an external load system, assuming that all the members are joined together by perfect pin- or ball-joints, then the secondary stresses are in general taken to be the additional stresses due to the rigidity of the actual joints used in practice.In such a highly redundant structure as an airship hull the labour involved, in determining even the primary stresses, precludes the use of the normal methods of stressing. It is usual to make use of generalised methods which give approximate results. These generalised methods imply that the external loads are applied to the structure in a certain distribution. Though this is rarely achieved, yet the results obtained are in most cases sufficiently accurate if suitable bracing is supplied to redistribute the external loads over the cross-section; the effect of the initial wrong distribution being then merely local.

Simulation and Analysis of Metal Microfluidic Heatsinks

2006 ◽  
Author(s):  
Alireza Motieifar ◽  
C. Shafai ◽  
H. M. Soliman
Keyword(s):  
Thermal Resistance ◽  
Cross Section ◽  
Fluid Velocity ◽  
The Body ◽  
Silicon Substrates ◽  
Channel System ◽  
Heat Conductance ◽  
Fem Method ◽  
Rectangular Channels ◽  
Electroplated Copper

Microfluidic heatsinks are usually fabricated in silicon substrates using micromachining methods. Fabrication of microfluidic heatsinks in metals is captivating due to the potential of higher heat conductance of many metals compared to silicon. In this work, metallic microfluidic structures fabricated of copper, silicon, and nickel are simulated and analyzed using the FEM method. The parametric dependence of the overall thermal resistance on the heatsink material, fluid velocity, and channel geometry is examined. Their performance is compared based on the shape and size of the microchannels, their separating distance from each other, and the flow rate. Simulations were done using FEMLAB v.3.2 (Comsol Multyphysics). The length of the microchannels considered is 1cm. Their cross section is rectangular. Simulated heatsinks are covered with 50 μm of the same material as the body and the total area of the heat sink is 1cm × 1cm. Water is used as the coolant with an input temperature of 300 K. These simulations show that most of the thermal resistance in the heatsink occurs in the fluid region. For the constant and uniform input heating power of 100 W/cm2 the performance of the structure is studied at steady state with the fluid velocity varied from 1 to 14m/s. Finally, experimental fabrication of an electroplated copper micro-channel system with rectangular channels is shown.

An Inverse Time Marching Method for the Definition of Cascade Geometry

1982 ◽  
Vol 104 (3) ◽  
pp. 650-656 ◽  
Author(s):  
G. Meauze´
Keyword(s):  
Velocity Distribution ◽  
Cross Section ◽  
Iterative Process ◽  
Suction Side ◽  
Wide Field ◽  
Closure Condition ◽  
Evolution Law ◽  
Time Marching ◽  
Definition Of ◽  
Marching Method

The article describes a so-called “inverse mode” calculation method, providing the geometry of a cascade corresponding to a given velocity distribution, and gives some examples of application. The velocity distribution may be assigned over the whole of the suction and pressure sides or over only a part of them, the remaining parts being already known. The closure condition of the profile is ensured by an iterative process on the solidity of the cascade. A second version allows the definition of the geometry of a profile with a given thickness evolution law and as assigned velocity distribution on the suction side. The method makes use of a pseudo-unsteady calculation, enabling one to treat the case of flows with shock waves in a two-dimensional stream with possible variations of cross section. This flexibility of use confers to the method a wide field of application, covering all possible configurations of flow in turbine and compressor cascades.

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